In 12-inch skillet, heat oil over medium-high heat. Add short ribs; sprinkle with salt and pepper. Cook 4 to 6 minutes, turning occasionally, until browned.
In 3- to 4-quart slow cooker, place tomatoes, onion and tomato paste; stir. Add ribs, wine, broth and Worcestershire sauce.
Cover; cook on Low heat setting 7 to 9 hours.
Remove ribs and bones from cooker; cover ribs to keep warm. Discard bones. Spoon off any fat from mixture in cooker. In small bowl, mix water and cornstarch; stir into mixture in cooker. Increase heat setting to High. Cover; cook 10 to 15 minutes longer or until sauce is thickened. Serve over ribs.